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Rupture process and energy budget of the 29 July 2008 M_w 5.4 Chino Hills, California, earthquake

Shao, Guangfu and Ji, Chen and Hauksson, Egill (2012) Rupture process and energy budget of the 29 July 2008 M_w 5.4 Chino Hills, California, earthquake. Journal of Geophysical Research B, 117 (B7). Art. No. B07307. ISSN 0148-0227. doi:10.1029/2011JB008856.

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The source model of the 2008 M_w 5.4 Chino Hills, California, earthquake is constrained using near-field seismic body waves recorded by the California Integrated Seismic Network (CISN). Finite fault inversions are preformed for the two fault models based on the nodal planes derived from the CISN moment tensor solution. The northeast dipping plane (strike = 289°; dip = 62°), which has a similar strike as the nearby Whittier fault, is chosen as the causative fault because it fits the data significantly better. Our inversion result indicates that the majority of the Chino Hills earthquake rupture occurred in a compact area. In particular, 48% of the total seismic moment (1.6 × 10^(17) Nm) was released by the failure of a 1.8 km^2 asperity located east of the hypocenter in a short time window from 0.4 to 0.8 s after the rupture initiation. The average slip is approximately 0.5 m but the maximum slip is 1.8 m. The average rupture velocity is 1.9 km/s. The static stress drop calculated using the slip model is up to 80 MPa and the average stress drop changes from 19 to 38 MPa, depending on the average schemes. The weighted average slip velocity is 6.5 m/s for entire rupture and is 11 m/s for the east asperity. The inferred available energy and radiated energy are 8 × 10^13 J and 2.5 × 10^13 J, respectively. Radiation efficiency is then 0.31, which is moderately low compared with previous earthquakes but consistent with the inferred high average fracture energy density, ranging from 6.5 to 14.8 MJ/m^2.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ji, Chen0000-0002-0350-5704
Hauksson, Egill0000-0002-6834-5051
Additional Information:© 2012 American Geophysical Union. Received 12 September 2011; accepted 5 June 2012; published 26 July 2012. We thank the constructive comments of the Associate Editor and three anonymous reviewers. We also thank Ross Stein and Martin Mai for their help on the stress drop calculation, Hiroo Kanamori for his help in radiated energy estimation, and Ralph Archuleta for the discussion of dynamic rupture. The strong motion waveforms were downloaded from the CISN data center ( Most figures were created using the Generic Mapping Tools (GMT) software [Wessel and Smith, 1998]. This work is partially supported by Dol-USGS 08CRGR0001 and partially supported by the Southern California Earthquake Center (SCEC) 120044, which is funded by the National Science Foundation (NSF) Cooperative Agreement EAR-0106924 and the U.S. Geological Survey (USGS) Cooperative Agreement 02HQAG0008. This article is contribution 1262 of SCEC and 0965 of the Institute for Crustal Studies (ICS).
Group:Seismological Laboratory
Funding AgencyGrant Number
Southern California Earthquake Center (SCEC)120044
Subject Keywords:Whittier fault; finite fault inversion; fracture energy; seismic-radiated energy; stress drop; 2008 Chino Hills earthquake
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)1262
Institute for Crustal Studies (ICS)0965
Issue or Number:B7
Record Number:CaltechAUTHORS:20120824-155856322
Persistent URL:
Official Citation:Shao, G., C. Ji, and E. Hauksson (2012), Rupture process and energy budget of the 29 July 2008 Mw 5.4 Chino Hills, California, earthquake, J. Geophys. Res., 117, B07307, doi:10.1029/2011JB008856.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:33533
Deposited On:24 Aug 2012 23:21
Last Modified:09 Nov 2021 21:35

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